In today's business world, reliable and efficient access to information has become an important asset in the quest to achieve a competitive advantage. File cabinets and mountains of papers have given way to computers that store and manage information electronically. Coworkers thousands of miles apart can share information instantaneously, just as hundreds of workers in a single location can simultaneously review research data maintained online.
Computer networking technologies are the glue that binds these elements together. One example of a computer network is known as an Ethernet network as illustrated in FIG. 1. The original Ethernet network described communication over a single cable shared by all devices on the network. Once a device attached to this cable, it had the ability to communicate with any other attached device. This allows the network to expand to accommodate new devices without requiring any modification to those devices already on the network. As illustrated in FIG. 1, the simple Ethernet network (100) may include multiple devices such as computers (110), printers (140), and servers (130) communicatively coupled through an Ethernet medium (120). During operation in a simple Ethernet network (100) such as that illustrated in FIG. 1, a signal placed on the Ethernet medium (120) will reach every attached node or device. A destination address is included in each signal, identifying the intended recipient of each data frame. For example, as illustrated in FIG. 1, when one of the computers (110) transmits to the printer (140), the other computers (110) and the server (130) will also receive and examine the address of the data frame. If the frame is not intended for the receiving component, the data frame will be discarded without examining its contents.
As networks began to expand, and multiple signals were transmitted over the networks (100), switched network systems were developed where each component is attached to the network communication medium via a switch. Even more recently, networks have evolved into what is known as a star topology in which all nodes (workstations or other devices) include individual switches that are directly connected to a common central computer through individual links.
Telecommunications service providers have also adopted the star topology. Often, service providers deploy a link demarcation device at the customer-network interface point which is often located at or near the customer premises. The link demarcation device acts as a physical demarcation point between the customer-owned and maintained infrastructure and the network-owned and maintained infrastructure, while allowing the service provider to isolate troubles to either the network-side of the device or the customer-side of the device. The link demarcation device may also provide a number of capabilities such as media conversion, rate conversion, performance monitoring, etc.
The traditional link demarcation devices that provide fault isolation have been both temporally and resourcefully inefficient. More specifically, to provide fault isolation, the traditional demarcation devices have to be actively managed through a signaling channel which is usually carried via the link that the link demarcation device demarcates, which is resourcefully costly in that it consumes bandwidth on the network link. In order to accommodate the signaling channel, the traditional link demarcation devices include the components and capability used to terminate the signal channel, carried via the network link, and to transmit complex signals, which incrementally increases their cost as well as using precious bandwidth.
Alternatively, the signaling channel could be forged inside the link's overhead to conserve user bandwidth, but this is a non-standard approach that requires deployment of another costly translation device to insert and extract the signaling channel into and out of the link's overhead at or near the link delimiting device. Finally, active management of the demarcation devices, and if needed, the translation device requires costly purpose-built management system software functionality.